1. Field of the Invention
The present invention relates to an identifying information access device for accessing RFID tag, and more specifically to an identifying information access device for accessing a gaming chip used in a casino and the like.
2. Description of the Related Art
A gaming chip having an integrated RFID tag is used in a casino and the like for the purpose of authentication and automatic measurement of the gaming chip. More specifically, an antenna for reading the RFID is provided on the underside of the gaming table, and a magnetic field is generated from the antenna. The identification information (a unique ID) of a betting chip has been detected in such a manner that an electromotive force is caused by the RFID tag so that the generated magnetic field penetrates the gaming chip placed on the gaming table (for example, refer to Japanese Patent No. 3839307 and Japanese Patent No. 4409540).
The range in which the magnetic field generated from the antenna extends is decided by the shape of the antenna and an output of an RF signal applied to the antenna. Therefore, when the distance between the RFID tag and the antenna is farther than a predetermined distance appropriate for the sensitivity of the RFID tag, the electromotive force for operating the RFID tag is not caused. Thus, it becomes difficult to read out a variety of information such as ID of the RFID tag.
If the range in which the magnetic field generated from the antenna extends is expanded, it is possible to read out the RFID tag positioned farther than the predetermined distance from the antenna. However, if there is an undesired RFID tag within the extent of the magnetic field, its RFID tag may be read out. Therefore, it has been desired to achieve the control for expanding the extent of the magnetic field generated from the antenna, as well as for extending the magnetic field only over a desired range.